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An amendment to this paper has been published and can be accessed via the original article.

Tamara Grummt passed away on January 26, 2020 in Oelsnitz/Vogtland, Germany. Tamara was one of the scientific pioneers in the field of environmental toxicology, namely genotoxicity and hygiene of drinking and bathing waters. Her passing is not only a great loss to environmental research and to the global environmental toxicology community—we have lost an outstanding personality with the heart in the right place, who has become, for many of us, a wonderful friend.

The present study explained the inhibitory effect of natural organic matter (NOM) on the photocatalytic degradation of clofibric acid (CA), and attempted to eliminate this inhibition by changing reaction conditions. The NOM degradation was followed by size-exclusion chromatography for dissolved organic carbon and ultraviolet absorption (SEC-DOC and SEC-UV254).The results demonstrated that the deactivation of NOM on catalyst was more dependent on the molecular weight of NOM than on its concentration. Higher molecular weight fractions were prone to adsorb onto the catalysts’ surface and acted as electron-hole scavengers and light filters to reduce the photocatalytic degradation rate of CA. pH adjustment changed the adsorption property of NOM, while, decreasing of its inhibition was not observed. However, the oxygen addition can significantly eliminate this inhibitory effect by increasing the degradation rate of high molecular size fractions of NOM.

In this work, the photocatalytic generation of free OH radicals ( OH free ) in aqueous TiO 2 suspensions was studied using an 18 O isotope labeling and a “remote” photocatalysis approach. A probe compound, 1,3,5-trichlorobenzene (TCB), was adsorbed in pores of silica gel (SG) microparticles and, by this, was shielded from the direct hole oxidation. Penetration of the TiO 2 particles (25 nm in size) to the TCB, adsorbed in the SG pores, was blocked due to a small size of the SG pores (4 nm). Therefore, the “remote” degradation of the TCB was solely driven by OH free , and this allowed us to selectively determine the quantum yield of the OH free generation. The isotope labeling with 18 O has demonstrated that the major pathway of the OH free formation is the direct hole oxidation of H 2 O, whereas the reduction of dissolved O 2 by photogenerated electrons contributes in less than 5% of the total amount of OH free . Nevertheless, the latter pathway becomes more important if holes are scavenged. This work sheds light on the intrinsic roles of photogenerated holes and electrons in the mechanism of the OH free formation in aqueous TiO 2 photocatalysis.

Natural organic matter (NOM) is ubiquitous in aquatic environment, which plays a predominant role in the sorption of pharmaceuticals onto the TiO 2 nanoparticles. It is a matter of concern whether NOM could act as a surface sensitizer of TiO 2 or not. In this context, the role of NOM is investigated for the photocatalytic degradation of carbamazepine (CBZ) using TiO 2 . Four different ratios of NOM:TiO 2 were used varying from 400 μg g −1 to 400 mg g −1 . The findings reveal that small amounts of NOM could enhance the TiO 2 efficiency up to 8%. Electron paramagnetic spectroscopy (EPR), along with size exclusion chromatography with dissolved organic carbon detection (SEC-OCD) and nuclear magnetic resonance spectroscopy (NMR) reveal the occurring mechanism. TiO 2 binds small molecular size fractions of NOM and breaks aromatic bonds of adsorbed NOM transforming it to stranded alkyl groups. This modified TiO 2 bears a significant amount of electrons (e − ) and lesser holes (h + ) than the purified TiO 2 and when irradiated, produces hydroxyl radicals which degrade CBZ.

In this study, a hazardous DNA-binding agent, bisphenol A 3,4-quinone (BPAQ), was detected among products of bisphenol A (BPA) photocatalytic degradation. To clarify the mechanism of BPAQ formation, we investigated BPA degradation by TiO 2 photocatalysis and UV photolysis at 254 nm in detail. The main focus was given to understanding the roles of OH radicals and photogenerated holes in the evolution of potentially harmful aromatic products. Five new intermediates were identified using an enhanced LC–MS–MS/ToF approach. We found that direct hole oxidation was abundantly responsible for the transformations of BPA into quinone and catechol products. Scavenging of free OH radicals induced a mechanism change and intensified BPAQ formation. Direct UV photolysis produced two catechol derivatives with potentially lower endocrine-disrupting activity in comparison to BPA. Both of the processes demonstrated similar efficiencies in BPA elimination. Complete mineralization was achieved only in the case of TiO 2 photocatalysis, but accompanied by potentially genotoxic intermediates formed by hole oxidation.

A simplified model of environmental conditions was developed to evaluate the effect of natural organic matter (NOM) and metal ions on the Pt/TiO2 photocatalytic degradation of diatrizoate and I - formation in the presence of different dissolved oxygen (DO) level. The results showed that the photocatalytic degradation of diatrizoate was strongly influenced by the amount of DO present and by the presence of metal ions. The DO concentration and the presence of NOM severely affected the formation of I - . The high R 2 values of the model signify that the models obtained are able to give a reasonably good estimate of response for the system in the range studied.

Application of nanofiltration (NF) membranes has increased during the last years: many industries from drinking water treatment and water re-use to the pharmaceutical and food industry deal with the application of NF and its drawbacks. One of the main problems of membrane technology is fouling. Fouling during NF is a complex problem because of the importance of the membrane surface properties (e.g. charge and structure) and the corresponding interactions between the water constituents and the membrane. In this work, the fouling layer composition of three membranes was investigated using different raw waters and it was correlated with the membrane performance. Rejection properties depended to a great extent on the water composition and the ionic strength of the raw water. Investigations of fouling layer compositions suggest that the membrane properties play a key role for flux decline and the related “amount” of fouling material on the membranes and its constituents.

The combination of ultrafiltration (UF) and powdered activated carbon (PAC) has gained in importance over the last 15 years. The aim of applying PAC-UF hybrid processes is to improve the rejection capacity and the performance of membrane processes. In this work the influence of PAC-addition on membrane flux decline and fouling formation was studied with a submerged module using different water matrices. The PACs used were characterized by measurements of the surface area, the particle size distribution and the surface charge to get a better understanding of the observed effects. Results showed that the membrane flux decline was dependent on the applied type of activated carbon. When adding Picachem 8P, the transmembrane pressure (TMP) increased very quickly and the membrane performance was even worse than that without PAC. However, when adding Norit SA-UF under identical filtration conditions, the TMP was stable and the membrane performance was better than that without PAC. The fouling layers of the two PACs applied showed entirely different structures. Therefore the selection of a suitable PAC is a main factor for the overall performance of PAC-UF hybrid systems with submerged membranes.

Much research has been undertaken on the photocatalytic degradation of humic substances with titanium dioxide using commercial humic acids (HA), which are extracts from either peat or coal. Most of the research has been focused on the changes in dissolved organic carbon (DOC) and UV254 absorption. These parameters only give a general assessment. This work studies the changes in the physical and structural properties of a commercial humic acid by size exclusion chromatography with DOC and UV254 absorption detection (SEC-DOC, SEC-UV254), and the evolution of halogenated organic compounds (AOX) and trihalomethanes (THMs) during the photocatalytic degradation with simulated solar UV irradiation and Degussa P-25 TiO2. These changes are compared with those reported for natural organic matter (NOM). The photodegradation of commercial HA and NOM proceeds in a similar and sequential manner, initially with the preferential adsorption of larger molecules, then the degradation of these larger molecular size fractions and proceeding towards smaller molecular size fractions, while decreasing THMs and AOX formation potential.

Nanoparticles (NP) are ubiquitous in environmental and technical aquatic systems. Understanding the role and the fate of NP in these systems is an interdisciplinary challenge requiring innovative experimental, theoretical and analytical approaches and critical reflection of classical concepts. This contribution critically reviews the outstanding properties of NP and the resulting consequences for their behaviour in environmental and technical aquatic systems considering natural NP which are mostly geogenic or biogeogenic, and engineered NP. Owing to the severe lack of data on the occurrence of NP in environmental aquatic systems, it is a key task of researchers to further develop analytical methods for the sensitive detection of NP directly in aqueous samples. There is urgent need for standardisation of analytical methods for detection and characterisation of NP, and for toxicity tests to assess possible adverse effects of NP. In this context, NP reference materials have to be defined as a common fundament for research in this field.

In this study an in vitro exposure test to investigate toxicological effects of the volatile disinfection by-product trichloramine and of real indoor pool air was established. For this purpose a set-up to generate a well-defined, clean gas stream of trichloramine was combined with biotests. Human alveolar epithelial lung cells of the cell line A-549 were exposed in a CULTEX® device with trichloramine concentrations between 0.1 and 40 mg/m3 for 1 h. As toxicological endpoints the cell viability and the inflammatory response by the cytokines IL-6 and IL-8 were investigated. A decreasing cell viability could be observed with increasing trichloramine concentration. An increase of IL-8 release could be determined at trichloramine concentrations higher than 10 mg/m3 and an increase of IL-6 release at concentrations of 20 mg/m3. Investigations of indoor swimming pool air showed similar inflammatory effects to the lung cells although the air concentrations of trichloramine of 0.17 and 0.19 mg/m3 were much lower compared with the laboratory experiments with trichloramine as the only contaminant. Therefore it is assumed that a mixture of trichloramine and other disinfection by-products in the air of indoor pool settings contribute to that effect.

Anaerobic degradation processes play an important role in contaminated aquifers. To indicate active biodegradation processes signature metabolites can be used. In this study field samples from a high-resolution multilevel well in a tar oil-contaminated, anoxic aquifer were analyzed for metabolites by liquid chromatography-tandem mass spectrometry and time-of-flight mass spectrometry. In addition to already known specific degradation products of toluene, xylenes, and naphthalenes, the seldom reported degradation products benzothiophenemethylsuccinic acid (BTMS), benzofuranmethylsuccinic acid (BFMS), methylnaphthyl-2-methylsuccinic acid (MNMS), and acenaphthene-5-carboxylic acid (AC) could be identified (BFMS, AC) and tentatively identified (BTMS, MNMS). The occurrence of BTMS and BFMS clearly show that the fumarate addition pathway, known for toluene and methylnaphthalene, is also important for the anaerobic degradation of heterocyclic contaminants in aquifers. The molar concentration ratios of metabolites and their related parent compounds differ over a wide range which shows that there is no simple and consistent quantitative relation. However, generally higher ratios were found for the more recalcitrant compounds, which are putatively cometabolically degraded (e.g., 2-carboxybenzothiophene and acenaphthene-5-carboxylic acid), indicating an accumulation of these metabolites. Vertical concentration profiles of benzylsuccinic acid (BS) and methyl-benzylsuccinic acid (MBS) showed distinct peaks at the fringes of the toluene and xylene plume indicating hot spots of biodegradation activity and supporting the plume fringe concept. However, there are some compounds which show a different vertical distribution with the most prominent concentrations where also the precursor compounds peaked.

The King Abdullah Canal (KAC) is an artificial water conveyor serving as raw water source for drinking water supply of Amman and for irrigation purposes in the Jordan Valley. The main water sources for KAC originate from the Yarmouk River, the Mukheiba Wells, and the Peace Conveyor. Water samples were collected from December 2002 to May 2004 to investigate changes in physicochemical parameters and parameters related to eutrophication along KAC. The catchment area of KAC is highly heterogeneous in terms of topography, climate, geologic conditions, and land use, resulting in great variations in the physicochemical composition of the canal water. The Yarmouk River and the Mukheiba Wells reflect the water quality of precipitation without much dissolution of halides, whereas the Peace Conveyor shows a groundwater characteristic. Main dischargers of N and P compounds are the Yarmouk River, and dams and wadis along KAC. The concentrations in the canal are mostly above eutrophication level for N and P. Along KAC ...

Herein we report on the photocatalytic degradation of natural organic matter from a bog lake (Lake Hohloh, Black Forest, Germany) as followed by size exclusion chromatography with dissolved organic carbon (DOC) and ultraviolet ( λ = 254 nm) detection (SEC-DOC and SEC-UV). When irradiating this humic-rich water in the presence of 0.5 g L−1 titanium dioxide (P25), we found a preferential degradation of the higher molecular weight DOC fraction. This was coupled to growth of the middle and small DOC fractions. Mineralization proceeded in two distinct steps: a first stage without noticeable mineralization, followed by a phase of steady decrease in dissolved organic carbon. Formic, oxalic, succinic and glutaric acids were found in the irradiated samples and contribute significantly to the bioavailable DOC after irradiation, which favors bacterial regrowth.

The efficiency of binding during enzyme immobilisation does not only depend on the chemical properties of the enzyme and the matrix particle, but also on their surface potential. Zeta potential quantifies the electrostatic interactions between enzyme and matrix particles, and can therefore, be used as an indicator of the binding efficiency in the enzyme immobilisation studies. In order to establish a correlation between the zeta potential and the binding efficiency, we used CALA (Candida antarctica A-type lipase) as a model protein for immobilisation on non-porous magnetic microparticles with epoxy (M-PVA E02), carboxy (M-PVA C12) and amine (M-PVA N12) terminations. We observed maximal binding of CALA onto the M-PVA N12 beads, due to the electrostatic attraction between negatively charged protein and carrier particles with slightly positive zeta potential. The binding of CALA was lower when M-PVA E02 beads were used, followed by M-PVA C12 beads. The decreasing binding efficiency was obviously the result of increasing electrostatic repulsion between the interaction partners. This could be correlated to the increasing negative zeta potential of the magnetic particles. Moreover, the medium of suspension of the particles also makes a significant difference. We found highest specific activity of the lipase immobilised on M-PVA E02 beads in a medium concentrated buffer (0.3 M). The results demonstrate a clear correlation between zeta potential and binding efficiency but no correlation between the bead related specific activity and the zeta potential. These findings are advocating the possibility of using the zeta potential as a diagnostic tool in enzyme immobilisation.

The application of membrane filtration in the treatment of spent filter backwash water (SFBW) permits efficient removal of microorganisms, suspended particles and organic substances, depending on the used membrane molecular weight cut-off. However, flux decline, due to deposits and adsorption of substances (salts, colloids, organics, particles, microorganisms, etc.) tends to limit the use of membranes. Characterization of SFBW samples from different waterworks showed that three major factors contribute to the SFBW properties: the raw water itself, the time interval of sand filter operation and additional treatment steps. The main differences between SFBW samples were found principally in DOC, TOC and turbidity. Experiments with submerged membranes (lab- and pilot- scale modules) showed that there was a clear correlation between DOC concentration of the feed and the flux decline: when the DOC-concentration increased, the flux decline increased. Additionally, the presence of calcium led not only to an important flux decline but to high adsorption of NOM on the membrane surface. Iron concentrations in the micromolar range resulted in a considerably decline of flux. Filtration of SFBW revealed that the decline of permeability is mainly determined by DOC, calcium and iron concentrations. A decisive effect of biofouling on membrane performance is expected for long term experiments.

The effects of four different filtration modes (i.e. relaxation, backwash, mixed and continuous) producing the same flux productivity (time average flux) on membrane fouling were investigated in membrane bioreactors (MBRs). The fouling behaviour was found to be strongly dependent on the applied instantaneous flux rather than the filtration modes themselves. The transmembrane pressure (TMP) obtained after 24 h of filtration was dominated by the fouling rates calculated within the first hour of the experiment. After the filtration experiments, the resulting fouling layers were fractionated by rinsing, backwashing and then chemical cleaning, with the foulant removal reflecting the strength of attachment to the membrane. An analysis of the three different fouling layers provided a unique insight into the composition (protein and carbohydrate) and spatial distribution of the particulate and soluble foulants. The upper fouling fraction consists of a porous, loosely bound cake layer with a similar composition to the biomass flocs. The intermediate fraction, which consists of equal parts of soluble molecular products (SMP) and biomass aggregates, features a higher concentration of carbohydrates and possibly plays a significant in the formation of consecutive cake layer. The lower fraction, representing the irreversible fouling fraction and predominantly consisting of SMP, features a relative higher concentration of strongly bound proteins. Whereas the lower and the intermediate fractions showed similar properties for all filtration modes, the upper fraction was influenced by the instantaneous flux.

Disinfection is mandatory for swimming pools: public pools are usually disinfected by gaseous chlorine or sodium hypochlorite and cartridge filters; home pools typically use stabilized chlorine. These methods produce a variety of disinfection byproducts (DBPs), such as trihalomethanes (THMs), which are regulated carcinogenic DBPs in drinking water that have been detected in the blood and breath of swimmers and of nonswimmers at indoor pools. Also produced are halogenated acetic acids (HAAs) and haloketones, which irritate the eyes, skin, and mucous membranes; trichloramine, which is linked with swimming-pool-associated asthma; and halogenated derivatives of UV sun screens, some of which show endocrine effects. Precursors of DBPs include human body substances, chemicals used in cosmetics and sun screens, and natural organic matter. Analytical research has focused also on the identification of an additional portion of unknown DBPs using gas chromatography (GC)/mass spectrometry (MS) and liquid chromatography (LC)/MS/MS with derivatization. Children swimmers have an increased risk of developing asthma and infections of the respiratory tract and ear. A 1.6-2.0-fold increased risk for bladder cancer has been associated with swimming or showering/bathing with chlorinated water. Bladder cancer risk from THM exposure (all routes combined) was greatest among those with the GSTT1-1 gene. This suggests a mechanism involving distribution of THMs to the bladder by dermal/inhalation exposure and activation there by GSTT1-1 to mutagens. DBPs may be reduced by engineering and behavioral means, such as applying new oxidation and filtration methods, reducing bromide and iodide in the source water, increasing air circulation in indoor pools, and assuring the cleanliness of swimmers. The positive health effects gained by swimming can be increased by reducing the potential adverse health risks.

Various leaching experiments applied to municipal waste incineration ash were compared in order to find the best available procedure to measure the total mass flow caused by natural leaching (source strength) of the material. The results of various batch experiments and two different laboratory column experiments run under water-saturated conditions were compared with water-unsaturated field-scale column experiments (lysimeter). The results of the batch experiments were not transferable to the column and field experiments. But, very good accordance could be observed between the breakthrough curves of the two column experiments conducted in the laboratory under water-saturated conditions and the water-unsaturated field-scale columns, with few exceptions. The results show that batch experiments are not sufficient to predict the source strength and its changes over time. Instead, column experiments are essential for a realistic risk assessment. For most inorganic parameters, a laboratory column experiment lasting less than 5 days is sufficient for a risk assessment in the foreseeable future.

Environmentally relevant polar persistent organic pollutants (pharmaceuticals and diagnostic agents) were chosen according to human consumption and occurrence in the aquatic environment (sewage plant effluents, rivers and groundwater) to investigate their behavior during photocatalytic oxidation. From data compilation in the literature, the active metabolite clofibric acid of some lipid lowering agents, the anti-epileptic drug carbamazepine and the X-ray contrast media iomeprol were selected. The degradation of the persistent pollutant was monitored by HPLC/DAD/FLD. The study also focuses on the identification and quantification of possible degradation products by HPLC/DAD/FLD and HPLC/MS/MS. The degradation process was also monitored by determination of sum parameters and inorganic ions. Various aromatic and aliphatic degradation products have been identified and quantified. From analytical data, a possible degradation scheme for carbamazepine was proposed. Kinetic studies showed that the TiO2 photocatalyst P25 was more active in clofibric acid degradation than Hombikat UV100. For photocatalytic degradation of iomeprol Hombikat UV100 was more suitable than P25. In general the presence of NOM and carbamazepine retarded the photocatalysis of clofibric acid. Radiation attenuation, competition for active sites and surface deactivation of the catalyst by adsorption are the reason for that. The results of this work proof that photocatalysis is a promising technology to reduce persistent substances even if they are present in low concentrations or in a complex matrix.

In this study natural organic matter (NOM) removal by ultra- and nanofiltration from four different raw waters was investigated. The experiments were carried out with a flat channel cross flow unit and with a pilot unit equipped with two parallel spiral wound modules. NOM rejection was characterized using 13CMAS-NMR spectroscopy, scanning electron microscopy (SEM) and size exclusion chromatography with online DOC detection (LC-OCD). Additionally measurements, such as DOC, UVA (254nm and 436nm), AOX- and THM-precursors, ion concentration, turbidity, etc. were made on raw waters, permeates and concentrates. The results indicate that NOM removal by nanofiltration for all water sources is almost complete (>90%), while NOM removal by ultrafiltration depends on raw water chemistry, especially ionic strength. Solid state 13C-NMR spectra of freeze-dried NOM deposits on membrane surfaces suggest the presence of structural polysaccharides (such as chitin and cellulose). SEM images confirm the NMR-results: after filtration, inorganic deposits and algae like structures were found on membrane surfaces.

The influence of an industrial waste water containing partly toxic and poorly biodegradable substances on an autotrophic biocenosis was investigated. Nitrifying bacteria were identified using fluorescently-labeled oligonucleotide probes and epifluorescence microscopy. Industrial waste water was used untreated and after ozonation to simulate the effects of indirect discharge to municipal waste water treatment plants. Results were compared to those obtained with acetate as a non-toxic and easily biodegradable substance and a mixture of acetate and pyruvate. The degradation of ammonium and the formation of nitrite and nitrate were measured and compared with the results obtained by fluorescence in-situ hybridization (FISH). The untreated waste water, containing higher amounts of refractory substances, disturbed nitrification, which was restored after reaching higher elimination of the organic substances. However, it showed only minor effects on the bacterial composition. These findings were similar to those reached by the addition of acetate and pyruvate. On the other hand, the ozonated waste water, showing higher toxicity than the untreated waste water, caused a stabilization in nitrification, but the composition of the population of ammonium-oxidizing bacteria changed significantly. In all cases, nitrite-oxidizing bacteria were only little affected both in activity and abundance.

Environmental contaminants of recent concern are pharmaceuticals, estrogens and other endocrine disrupting chemicals (EDC) such as degradation products of surfactants, algal and cyanobacterial toxins, disinfection by-products (DBPs) and metalloids. In addition, pesticides (especially their transformation products), microorganisms, and humic substances (HS), in their function as vehicles for contaminants and as precursors for by-products in water treatment, traditionally play an important role. The present status of the application of LC-MS techniques for these water constituents are discussed and examples of application are given. Solid-phase extraction with various non-selective materials in combination with liquid chromatography (LC) on reversed-phase columns have been the most widely used methods for sample preconcentration and separation for different compound classes like pesticides, pharmaceuticals or estrogens. Electrospray ionization (ESI) and atmospheric pressure ionization (APCI) are the most frequently used ionization techniques for polar and ionic compounds, as well as for less polar non-ionic ones. The facilities of LC-MS have been successfully demonstrated for different compound classes. Polar compounds from pharmaceuticals used as betablockers, iodinated X-ray contrast media, or estrogens have been determined without derivatization down to ultratrace concentrations. LC-MS can be viewed as a prerequisite for the determination of algal and cyanobacterial toxins and the homologues and oligomers of alkylphenol ethoxylates and their metabolites. Tandem mass spectrometric techniques and the use of diagnostic ions reveal their usefulness for compound-class specific screening and unknown identification, and are also valid for the analysis of pesticides and especially for their transformation products. Structural information has been gained by the application of LC-MS methods to organometallic species. New insights into the structural variety of humic substances have been made possible by FT-ICR-MS due to its ultrahigh mass resolution. Finally, exciting possibilities for rapid detection and identification of microorganisms have been made possible by MALDI and LC-MS methods.

LC-MS has become an invaluable technique for trace analysis of polar compounds in aqueous samples of the environment and in water treatment. LC-MS is of particular importance due to the impetus it has provided for research into the occurrence and fate of polar contaminants, and of their even more polar transformation products. Mass spectrometric detection and identification is most widely used in combination with sample preconcentration, chromatographic separation and atmospheric pressure ionization (API). The focus of the first part of this review is directed particularly toward instruments and method development with respect to their applications for detecting emerging contaminants, microorganisms and humic substances (HS). The current status and future perspectives of 1) mass analyzers, 2) ionization techniques to interface liquid chromatography (LC) with mass spectrometry (MS), 3) methods for preconcentration and separation with respect to their application for water analysis are discussed and examples of applications are given. Quadrupole and ion trap mass analyzers with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are already applied in routine analysis. Time-of-flight (TOF) mass spectrometers are of particular interest for accurate mass measurements for identification of unknowns. For non-polar compounds, different ionization approaches have been described, such as atmospheric pressure photoionization (APPI), electrochemistry with ESI, or electron capture ionization with APCI. In sample preconcentration and separation, solid phase extraction (SPE) with different non-selective sorbent materials and HPLC on reversed-phase materials (RP-HPLC) play the dominant role. In addition, various on-line and miniaturized approaches for sample extraction and sample introduction into the MS have been used. Ion chromatography (IC), size-exclusion chromatography (SEC), and capillary electrophoresis (CE) are alternative separation techniques. Furthermore, the issues of compound identification, matrix effects on quantitation, development of mass spectral libraries and the topic of connecting analysis and toxicity bioassays are addressed.

The fate of pharmaceuticals in surface waters under solar irradiation was investigated. Photodegradation of pharmaceuticals caused by sun irradiation may be of major significance in the natural elimination process. Based on a data compilation from the literature, the lipid lowering agent metabolite clofibric acid, the iodinated X-ray contrast media iomeprol, which contribute to the adsorbable organic halogen compounds, and the antiepileptic drug carbamazepine were selected. The irradiation experiments were carried out in batch experiments with simulated UV-sunlight. The photodegradation of the pharmaceuticals showed a pseudo-first-order kinetics. The objective of this investigation was to demonstrate that the extent of photoinduced degradation of pharmaceuticals can vary significantly for the different pharmaceuticals and it strongly depends on the water constituents present in solution. The influences of different initial pharmaceutical concentrations, the presence of other pharmaceuticals like carbamazepine or clofibric acid and the presence of natural organic matter on the photochemical degradation rate of pharmaceuticals in aqueous solutions were investigated. Analyses of the pharmaceuticals and their photodegradation products were carried out by high performance liquid chromatography with diode-array and fluorescence detection.

In the present study an analytical method was optimized for the determination of alpha-endosulfan, beta-endosulfan, endosulfan sulfate, endosulfan ether and endosulfan lactone in small volumes of environmental aqueous samples using solid-phase microextraction (SPME) and gas chromatography-electron capture detection (GC-ECD). A 100 micro m polydimethylsiloxane (PDMS) phase was used for the extraction. The limit of detection (LOD) for the analytes varied between 0.01 and 0.03 micro g L(-1) with a relative standard deviation of 3 to 11%. The influence of the ionic strength on the extraction efficiency was investigated for the individual compounds. alpha-Endosulfan, beta-endosulfan, endosulfan sulfate and endosulfan ether were extracted successfully without salt addition. The extraction efficiency of endosulfan lactone was improved with 30% NaCl content. A general decrease in extraction efficiency for alpha-endosulfan, beta-endosulfan, endosulfan sulfate and endosulfan ether with high NaCl content (20-30%) in the solution was observed due to glass surface adsorption. No effect of dissolved organic material (DOM) on the extraction efficiency was observed. The extraction coefficients changed between Log K=2.17 and 3.33. A sample from the Antarctic region was analyzed using the optimized GC-ECD/SPME method. To confirm the results obtained for the real sample a GC with a mass spectrometer (MS) was used. Endosulfan sulfate, the most toxic metabolite of endosulfan, was found in the sample at a concentration of 0.3 micro g L(-1).

Chlorination and ozonation experiments under conditions close to drinking water treatment were carried out with two different tap waters with low DOC content and water from a bog lake with high natural organic matter content. THM formation was low and in the range of 10 μg/L. Derivatization with dinitrophenylhydrazine and HPLC/tandem mass spectrometry were applied to measure carbonyl DBPs by precursor ion scans at m/z 163 for aldehydes and at m/z 182 for dicarbonyls. Formaldehyde, acetaldehyde, glyoxal, and methylglyoxal were formed by chlorination and ozonation. Ozonation produced the highest levels of carbonyls, in particular in the tap water samples. A strategy for structure suggestion and identification of unknown compounds on the basis of collision-induced dissociation (CID) mass spectra (MS) is given. The resulting structures are carbonyls with additional hydroxy and carboxy groups and serve for choice or synthesis of standard compounds for further identification. The possibilities and limits of compound identification are discussed.

In this work ozonation in combination with microbiological treatment was employed to remove ligninsulfonic acid and refractory organic substances from the effluent of a paper mill wastewater treatment plant. In laboratory experiments it was shown that ligninsulfonic acid was converted into low-molecular-weight acids, which were biodegradable. At an ozone/DOC ratio of 1.68 a DOC elimination of 22.2 % and a decrease of the UV absorbance of 56.9 % was achieved. For the pilot-scale experiments with the paper mill effluent the DOC elimination and the decrease of the UV absorbance were 46.1 % and 72.2 %. respectively. This was due to the high ozone/DOC ratio of 3.1 applied in these experiments. The high ozone dose did not lead to a significant conversion of the organic substances, but to a complete oxidation of the DOC.

The adsorption behavior of organic substances from different industrial wastewaters onto activated carbon (F 300) was compared with the adsorption onto an organic polymer resin (Lewatit EP 63). The adsorption capacity of Lewatit EP 63 was lower at low equilibrium concentrations and similar at high equilibrium concentrations compared with activated carbon. The adsorption behavior is represented in similar portions for high K values for both sorbents obtained with the adsorption analysis. Steady-state and time-resolved fluorescence measurements showed that the fluorescent components of the wastewaters were not adsorbed on Lewatit EP 63 which means that there was selective adsorption.

A method has been developed for quantitative determination of carbonyl disinfection by-products (DBP) from aqueous samples by derivatization with 2,4-dinitrophenylhydrazine combined with high-performance liquid chromatography (HPLC) and electrospray ionization (ESI) tandem mass spectrometry (MS-MS). The effect of excess of derivatization reagent and derivatization time, the effect of buffer and dry-gas temperature in the ESI process, and the effect of focus potential and collision energy in MS measurement are shown. Major fragment ions for compound identification on the basis of collision-induced dissociation (CID) mass spectra (MS) are given, as are common fragments for screening analyses by MS experiments such as the use of precursor ion scans. Detection limits in the microg x L(-1) range could be achieved by selected ion monitoring measurements without sample preconcentration. Solid-phase extraction improved the sensitivity by a factor of 25 to 250. The applicability of the method is illustrated by DBP analyses of samples from outdoor swimming pools after chlorination. Several carbonyl compounds, e.g. aldehydes, ketones, hydroxybenzaldehyde, and dicarbonyl compounds were identified.

The three metabolites hydroxyibuprofen (OH-Ibu), carboxyibuprofen (CA-Ibu), and carboxyhydratropic acid (CA-HA), also known from human metabolism of ibuprofen, could be identified in biodegradation experiments. Identification was based on EI mass spectra and comparison with literature data. Detection was performed by selective MS-MS measurements by GC-ion-trap MS and online methylation. Ibuprofen (Ibu), OH-Ibu, and CA-Ibu could be detected with a signal-to-noise ratio of 10:1 at a concentration of 2 nmol L(-1), CA-HA at 0.5 nmol L(-1). Degradation experiments in both biofilm reactors (BFR) and batch experiments with activated sludge (BAS) reveal OH-Ibu as the major metabolite under oxic conditions, and CA-HA under anoxic conditions. CA-Ibu was found under oxic and anoxic conditions almost only in the BAS. The metabolites together do not account for more than 10% of the initial concentration of Ibu.

Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity e=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

To find out more on the structure of humic substances (HS), isolated dissolved organic carbon (DOC) samples from a brown water lake and a wastewater effluent were fractionated and subjected to alkaline hydrolysis. UV/Vis and fluorescence spectroscopy, as well as size-exclusion chromatography with on-line detection of UV absorption, fluorescence and DOC concentration were used to investigate the structural changes caused by the hydrolysis reaction. Following hydrolysis, the fluorescence intensity increased considerably despite a decrease in the UV absorption. The UV absorption and the DOC data from the SEC experiments revealed a strong shift to smaller molecular sizes after hydrolysis. The spectra of the hydrolysed samples, as well as the size-exclusion chromatograms, were compared to spectra of hydroxybenzoic acids and hydroxycinnamic acids. From this comparison, it can be concluded that the hydrolysis products have a structure similar to these organic acids.

Le travail scientifique depend toujours de savoirs specifiques deja acquis. Ceci s'applique notamment au domaine de la chimie des substances aquatiques. Certaines etapes importantes ont ete : (1) la standardisation des procedes d'isolement des substances humiques et avec elle la disponibilite de substances de reference ; (2) l'application des outils puissants de la spectroscopie RMN et de la spectrometrie de masse combines a la pyrolyse pour identifier les blocs moleculaires constitutifs ; (3) l'application de la chromatographie sur gel avec detection multiple y compris la spectroscopie vibrationnelle et electronique et la mesure en ligne pour la caracterisation directe de la matiere organique dans les echantillons aquatiques ; (4) l'application de la fluorescence statique et resolue en temps pour etudier les etats excites et la formation de complexes ; (5) l'etude des reactions avec des partenaires bien definis et (6) le developpement des modeles informatiques pour les structures moleculaires dont le niveau d'energie est minimum.

Due to their heterogeneity and polydispersity, refractory organic substances (ROS) play a multifunctional role in the natural environment and in water treatment processes. Those properties also complicate an authentic analytical characterization. Since ROS are ubiquitous in natural waters and as they have the potential to form toxic disinfection by-products research aims at the characterization of their behavior in water treatment processes. Gel chromatography in combination with UV/Vis and sensitive dissolved organic carbon detection is shown to be useful, yielding information on molecular absorbance, molecular mass distribution, and reactivity. Additional experiments under defined conditions lead to information about the fate of ROS during biological, oxidation and adsorption processes. It is shown that ozonation, peroxonation, and chlorination result in partial decomposition of high molecular mass structures to low molecular hydrophilic compounds which are more bioavailable for microorganisms. In contrast to this, adsorption using activated carbon removes organic fractions of lower molecular mass, whereas the high molecular mass compounds of ROS showing relative high UV absorbance remain in solution. Based on this partial decomposition to smaller and therefore better bioavailable compounds oxidative processes can be used to improve the efficiency of waste water treatment.

The influence of natural organic matter (NOM) on the desorption kinetics of pyrene and naphthalene adsorbed on quartz was examined in batch experiments. Online determination of the concentration of the polycyclic aromatic hydrocarbons (PAH) in the aqueous phase was performed using fluorescence detection. Desorption experiments were done in a Completely Mixed Batch Reactor (CMBR) using PAH loaded quartz as model soil. A diluted pyrophosphate extract and a water extract of a well characterized soil, water of a bog lake (Hohlohsee, Black Forest), and deionized water were used as aqueous phases. The experimental data were fitted to two mathematical models: (1) an empirical model and (2) the diffusion film model. Both models were able to describe the concentration profile of the dissolved PAH quite well. Whereas the desorption rate of naphthalene decreased in the presence of NOM, no significant influence of NOM on the desorption kinetics of pyrene was observed. In this context, neither the origin nor the concentration of the different NOM had a significant impact on the values obtained.

The FA and HA fractions represent 20 to 50% of the DOC of the original samples, depending on the origin, and serve as reference materials. The original aqueous samples and the aqueous solutions of the reference materials were characterized with methods suited for measuring samples at natural concentrations. The DOC normalized values of the spectral absorbances (λ = 254 nm; λ = 436 nm) in the original water samples were highest for the brown water and brown coal water and lowest for the secondary effluents. The FA fractions were similar in the UV-absorbance with the exception of the low-absorbing groundwater FA, reflecting a low density of double bonds. The DOC-normalized proton capacity of the FA fractions (10 to 20 μmol/mg) was highest for the brown coal, brown water, and soil-derived samples and again lowest for the groundwater FA. The high values are due to a higher contribution of the weak acids of phenolic type. Specific data for copper complexation capacity (0.5 to 2.5 μmol/mg) went parallel to the proton capacity. The characterization of the FAs by gel chromatography with organic carbon detection revealed three major fractions. The refractory part at short retention time dominated in the brown water and soil-derived samples, whereas the fractions for the lower molecular mass acids at long retention times were dominant in the secondary effluent and the brown coal isolate. Comparison with UV-detected chromatograms revealed a strong decrease in the specific absorbance of the secondary effluent. Up to 3% of the total mass of the FAs could be identified as hydrolyzable amino acids with the highest yield in the sample from secondary effluent and the lowest one in the groundwater sample. The nitrogen content was always higher in the FAs compared to the HAs of the same origin. The application of gel chromatography fluorescence and fluorescence decay time distribution analysis turned out to be a useful tool to differentiate between the different fractions of NOM, the isolates obtained by different methods (e.g., XAD-8, membrane separation) and the fractions of the samples from different origin and age. This is of special value, for the information can also be obtained for samples with natural NOM concentrations, even though further investigations required for full understanding of the data. This work is part of a multi-disciplinary research program (ROSIG: Refraktare Organische Sauren in Gewassern), funded by the German Research Association (DFG).

NOM (natural organic matter) samples, isolated by reverse osmosis (RO), and nine NOM samples, concentrated by low-pressure, low-temperature evaporation (EVA) from various origin in Norway, were characterized by different methods. The methods included elemental content of the freeze-dried samples (C, H, N, and O), elemental content of the redissolved samples (DOC, Na, Ca, Cu, Fe, and Mn), specific spectral absorbance at λ = 254 nm (A(254 nm)/DOC) and at λ = 436 nm (A(436 nm)/DOC), UV/Vis-spectra, specific fluorescence (excitation and emission spectra), proton capacity, Cu-complexation capacity, and content of hydrolysable amino acids and carbohydrates. In addition, chromatographic characterization by gel chromatography and reversed-phase chromatography was done. Studies on adsorption and flocculation abilities and the formation of trihalomethanes (THM) and organic halogens adsorbable on activated carbon (AOX) upon chlorination were also investigated. Comparison of the results showed that the samples were different according to the origin of the sample, isolation procedure, and time of sampling. The differences are not the same for all parameters used. Standardized procedures have to be applied to redissolve the organic material in water in order to compare data. For the samples investigated, it was shown that parameters like elemental analysis (H/C ratio), the specific spectral absorption in the UV range, proton capacity, complexation capacity and anionic particle charge, amount of hydrolysable amino acids and carbohydrates, adsorption behaviour on activated carbon, and the THM-FP are sensitive parameters to show differences concerning origin and isolation procedure.

Natural organic matter (NOM) is ubiquitous in global aquatic systems, the mass concentrations ranging from 0.5 to 100 mg/l of organic carbon. The polydispersity of molar masses and the chemical structures comprising NOM give it a multifunctional role in natural environment and in water treatment processes. Important functions include serving as an electron donor in metal complexation, sorption of xenobiotics and adsorption onto mineral phases and onto activated carbon. NOM is partially oxidized during microbial utilization and during water treatment in which it may also become substituted with chlorine leading to a suite of products with toxic relevance. Meaningful methods of NOM characterization would be useful for the development of a predictive capacity for NOM behaviour in different water sources. Among analytical characterization methods, those directly applicable to aqueous samples are most useful and in addition to classical spectroscopic methods, more advanced methods have become available within the last decade. High pressure liquid chromatography using gels have proved useful in combination with UV/vis, fluorescence, light scattering and sensitive dissolved organic carbon detection techniques, yielding information on molecular absorbance, size distribution, molar mass and reactivity. Information on biodegradability of NOM can be deduced from experimental measurement of bacterial growth under defined conditions. The nature and amount of biologically assimilable organic carbon (AOC) in combination with the bacterial cell number and growth rate constants can provide a meaningful characterization of microbial stability in aquatic systems. In addition, determination of directly available and acid or enzymatically hydrolysable amino acids and carbohydrates can add to the understanding of NOM biodegradability over different time scales. The paper gives the results obtained by the application of the different methods for the characterization of aquatic NOM and its fractions of different origin. It can be shown that the availability of advanced characterization techniques offers the potential for predicting the functionality of aquatic NOM without precise knowledge of the chemical structures present in the macromolecular complex.

In recent years, the ozone treatment technique has been discussed for remediation of contaminated sites. In this paper, data on the effects of ozonation of soil organic matter in ground and pore waters are presented. An aqueous soil extract was ozonated in a stirred tank reactor and characterized by size-exclusion chromatography with online UV and dissolved organic carbon detection. Additionally, degradation experiments were carried out with these extracts in a bacteria regrowth measurement system. After ozonation, a decrease of the humic acid fraction and a reduction of its average molecular size could be recognized. In contrast to this, there was an increase of the building block fraction and the low molecular acid fraction. These two fractions were readily degradable by microorganisms. Therefore, the bacteria regrowth increased with ozonation time. As a result of this, a fast and high regrowth of bacteria can be expected after the ozone remediation technique has been applied. The UV absorbance of extracts at a wavelength of 254 nm showed no significant changes before and after biological degradation. It can be supposed that the microorganisms were not able to degrade chromophoric groups absorbing at a wavelength of 254 nm.

In this work a systematic characterization of the fluorescence kinetics of fulvic acid by means of a single-photon time correlation technique is reported. The data were extracted from both single decay curves and time-resolved emission spectra and analyzed by the exponential series method. The results strongly suggest the existence of a tri-modal decay time distribution with peak decay time values centred around 0.7, 3 and 10 ns. The relative amplitudes of the decay time distributions were shown to depend on the emission wavelength, indicating a three-species mixture with slightly different emission maxima and widths. As sustained by time-resolved emission spectra the same species of fluorophores are responsible for the fluorescence kinetics behaviour of fulvic acid at all excitation wavelengths used in the experiments. For the first time these techniques and methods were applied in investigating the effects of the Eu 3+ complexation upon fluorescence kinetics of the fulvic acid. Single decay analysis indicates that the peak decay time values are not affected by Eu 3+ addition at all emission and excitation wavelengths used in the experiments. On the contrary, the dependency of relative amplitudes on emission wavelength was greatly reduced in comparison with the uncomplexed fulvic acid. This effect is further evidenced by analysing the barycenter transients of time-resolved emission spectra. Finally, it is also indicated that within the temporal resolution of the experimental set up used the singlet states play no role as donor states in intramolecular energy transfer from the organic fulvic acid ligands to the Eu 3+ energy levels.

Natural organic matter (NOM) has the property to absorb light in the UV and visible range. Derived from the stratospheric ozone depletion, there is a reasonable concern about the influence of lower wavelength irradiation on the role of NOM in aquatic systems. Experiments were performed under defined conditions simulating sunlight with increased UV-B content for irradiation of NOM in aerated and deaerated aqueous solutions. The results show that there is a general bleaching effect in the irradiated samples and a change in the molecular size distribution of NOM. Irradiation causes a decrease in the higher molecular range and an increase of smaller molecules, along with an increase of the assimilable amount of organic matter. The toxicity for Daphnia magna is higher in irradiated samples, especially in deaerated ones. A decrease in the resolution of the lifetime distribution and a shift of the maximum lifetime to longer values are found for time-resolved fluorescence. Steady-state fluorescence shows an increase of the relative intensities with decreasing wavelength in case of the aerated samples, and the reverse tendency for the deaerated ones.

The distribution of heavy metals in the aqueous phase of aquifers is strongly dependent on the kind of solid phase and on the presence of dissolved organic matter. Batch experiments were performed to investigate the phase distribution of Cd, Pb, and Cu using Quartz, Potassium Feldspar, Sodium Feldspar, Kaolinite, Calcite, and Fe/Mn-coated Quartz sand as mineral phases. Natural organic matter (NOM) from a brown water lake was used to study its influence on the phase distribution of the metals. From the experimental results, Freundlich isotherms were calculated. They turned out to be suited for a description of the heterogeneous systems. Despite the obvious limitations of mechanistic interpretation, NOM increased the dissolved fraction of Cu and Pb, and decreased that of Cd.

The influence of H2O2 on the UV degradation of the broadly used aminopolycarboxylates EDTA and NTA in aqueous solution was investigated. The photochemical degradation in the UV /H2O2 process was compared with classical oxidative treatment of potable water. The German drinking water regulation (Trinkwasserverordnung) was the orientation for all experiments. The Advanced Oxidation Process (AOP) turned out to be superior to the classical oxidation processes. The photochemical degradation of EDTA and NTA by UV irradiation could be significantly stimulated in the presence of H2O2. There was a strong increase in the degradation rate and a decrease in the quantum yield of the aminopolycarboxylates. Experiments with butyl chloride as radical scavenger proved the photolytically generated hydroxyl radicals to be responsible for the increase in the degradation rates. The effect of increasing the degradation rate at higher concentrations of H2O2 was limited, because the steady-state concentrations of the hydroxyl radicals as reactive species, did not increase at the same rate as the initial concentration of H2O2. Low amounts of iron dissolved from the high-grade steel photoreactor walls had a significant catalytic effect on the degradation.

The enzymatic cleavage of the amide bond of l -leucine-4-nitroanilide by the proteolytic enzyme Pronase E releases 4-nitroaniline. The production of this molecule can be observed by the increasing UV absorption of the solution. A decrease in the rate of hydrolysis reaction was obtained in the presence of different humic substances isolated from water, sediment and soil. This result indicates that humic substances influence enzyme activity by interacting with the applied enzyme. A mathematical relation between the concentration of humic substances and their inhibition effect was used to calculate an effective concentration for which 50% of the maximum effect was observed. The obtained concentration was defined as the EC 50 value. The EC 50 values of the investigated humic substances were in the range 153 mg l −1 to 6360 mg l −1 . The amounts of humic substances used in the experiment were higher than in most aquatic environments. However, in bog water or interstitial water of sediments and soils such large amounts of biologically and ecologically relevant natural organic matter can be expected.

In order to elucidate the rejection properties of FT30 membranes, reverse osmosis experiments were carried out with varying ion concentration (1–40 mol/m 3 ), ion composition, transmembrane pressure drop (1–3 MPa) and pH (4–10). As model solution for each experiment demineralized water was used containing known amounts of salts such as NaCl, NaNO 3 , KCl, KNO 3 , Na 2 SO 4 and CaCl 2 either single or in combination. Some experiments were made with solutions containing compounds that cause fouling of the membrane such as Fe(OH) 3 or humic substances. Specific rejection and overall salt rejection were determined by measuring the ion concentrations and electrical conductivity in samples of the permeate and concentrate. The results showed an increase of rejection with transmembrane pressure drop and a decrease in rejection with increasing concentration, whereby the latter effect was more distinct in mixed salt solutions than in single salt solutions. Rejection of anions and cations increased with pH as the membrane charge became more negative. Multivalent ions were better rejected than univalent ions. Nitrate was better rejected as single solute than in combination with other salts in solution. If fouling layers were formed on the membrane surface, the rejection properties changed. Fouling layers made of iron hydroxide caused a marginal decrease in salt rejection whereas fouling layers made of humic substances caused an improvement of salt rejection under the conditions used.

Water analysis is dominated by parameters given in laws and recommendations concerning water quality. Speciation has been broadly neglected. This might be due to the difficulties in defining speciation and in determining species at low concentrations. This paper addresses the physical, chemical and biological approaches to speciation and gives examples for methods which are suited for species determination in aquatic systems. Metals and non-metallic elements are covered as well. It is obvious that speciation is a key for understanding the function of aquatic ecosystems and their technical utilization.

The adsorption behaviour of humic substances on activated carbon was different for samples of different origin. Humic substances isolated from bog lakes or from aqueous soil solutions are less adsorbable than those from rivers, groundwater, or samples from landfill leachates. The adsorption behaviour was determined by different physical and chemical parameters. The experimental data could be described by model calculations based on Freudlich equations for two fictive components of the total dissolved organic carbon. The nominal molecular weight distribution of humic substances from bog lakes and soil solution showed relatively high values. In addition, these substances had pronounced aromatic structures. This goes along with a relatively weak adsorption on activated carbon. There was no clear correlation concerning the hydrophilic character of the humic substances and their acidic character (proton capacity). Humic substances isolated from river water, groundwater, and landfill leachates showed lower nominal molecular weight and lower UV-absorbance. They had a higher aliphatic character and were more readily adsorbed on activated carbon than the other samples. The findings are of technical importance for water treatment.